1. Field
The present disclosure relates generally to light-emitting diode (LED) bulbs and, more specifically, to an LED bulb having an adjustable light-distribution profile.
2. Related Art
Traditionally, lighting has been generated using fluorescent and incandescent light bulbs. While both types of light bulbs have been reliably used, each suffers from certain drawbacks. For instance, incandescent bulbs tend to be inefficient, using only 2-3% of their power to produce light, while the remaining 97-98% of their power is lost as heat. Fluorescent bulbs, while more efficient than incandescent bulbs, do not produce the same warm light as that generated by incandescent bulbs. Additionally, there are health and environmental concerns regarding the mercury contained in fluorescent bulbs.
Thus, an alternative light source is desired. One such alternative is a bulb utilizing an LED. An LED comprises a semiconductor junction that emits light due to an electrical current flowing through the junction. Compared to a traditional incandescent bulb, an LED bulb is capable of producing more light using the same amount of power. Additionally, the operational life of an LED bulb is orders of magnitude longer than that of an incandescent bulb—for example, 10,000-100,000 hours as opposed to 1,000-2,000 hours.
Although LEDs provide advantages in efficiency and lifetime, they also present various design challenges related to heat dissipation and light distribution. LEDs are about 80% efficient, meaning that 20% of power supplied to LEDs is lost as heat. In many cases, an LED bulb is operated so that the heat produced is below an acceptable threshold level. Preventing an LED from reaching excessive temperatures may maximize the lifetime of the LED and also maximize the overall light output. The operating temperature of LEDs in an LED bulb depends on multiple factors, including the number of LEDs, the type of LEDs, and the thermal properties of the bulb. Traditionally, the heat from the LEDs is conducted through an LED mount to a base of the bulb, where it is dissipated to the surrounding environment.
Another challenge associated with LED bulbs is that the light distribution of the LEDs tends to be highly dependent on direction. That is, in at least some cases, an LED emits significantly more light in certain directions than it does in others. Thus, the placement and orientation of the LEDs in an LED bulb have a significant impact on the light-distribution profile of the device. If the placement of the LEDs is adjustable (as described in some embodiments below), additional difficulties may arise when dissipating heat through the base of the bulb, as done in some traditional LED bulbs.
Thus, there is a need for an LED bulb that allows for adjustable placement of the LED while also dissipating a sufficient amount of heat to ensure reliable operation of the LEDs.